diff --git a/c/console/expressions/expressions.c b/c/console/expressions/expressions.c
index ea2ad56..0be445d 100644
--- a/c/console/expressions/expressions.c
+++ b/c/console/expressions/expressions.c
@@ -2,6 +2,8 @@
 #include <math.h>
 
 int main() {
+  const float pi = 3.141592653589793f;
+  
   float a = 10.f, b = 15.f, c = 20.f;
   float result;
 
@@ -9,11 +11,11 @@ int main() {
   printf( "Area of triangle with sides %f, %f and %f is %f\n",
           a, b, c, result );
 
-  result = (1.f/3.f)*M_PI*a*(b*b);
+  result = (1.f/3.f)*pi*a*(b*b);
   printf( "Volume of cone with height %f and radius %f is %f\n",
           a, b, result );
 
-  result = (4.f/3.f)*M_PI*a*b*c;
+  result = (4.f/3.f)*pi*a*b*c;
   printf( "Volume of ellipsoid with radiuses %f, %f and %f is %f\n",
           a, b, c, result );